Feature Packs enable you to extend Visual Studio 2010 with capabilities that enhance and complement the existing tools. These releases expand the scenarios where you can use Visual Studio to help you create better software. Check-out what’s now available in the Visualization and Modeling Feature Pack (MSDN Subscribers Only) feature pack:

Expand the scenarios for exploring and understanding your code.

• Generate code from UML class diagrams.
• Create UML class diagrams from code.
• Import UML class, sequence, and use case elements from XMI 2.1 files.
• Create and view links from work items to model elements.
• Generate dependency graphs for ASP.NET Web, C, and C++ projects.
• Create and validate layer diagrams for C and C++ code.
• Write custom code to create, modify, and validate layer diagrams.

UML Class Diagram Code Generation
VS Ultimate 2010 added support for the most popular UML diagram types including Class Diagrams.  This release also adds the ability to generate code from your UML diagram targeting the correct T4 template.  Here is a sample class diagram for customers with orders:
 

Once you have your your diagram, simply right click and select “Generate Code”:

Check-out this blog post by Jasonz for more details about this and more functionality with the VS2010 feature Packs: